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Chūō-ku, Japan

Kaneai N.,Shibaura Institute of Technology | Sumitani K.,Shibaura Institute of Technology | Fukui K.,Shibaura Institute of Technology | Koike T.,Eisai Food and Chemical Co. | And 2 more authors.
Journal of Clinical Biochemistry and Nutrition | Year: 2016

To define whether tocotrienol (T-3) improves cognitive deficit during aging, effect of T-3 on learning and memory functions of aged rats was assessed. It was found that T-3 markedly counteracts the decline in learning and memory function in aged rats. Quantitative analysis of T-3 content in the rat brain showed that the aged rats fed T-3 mixture-supplemented diet revealed the transport of α- and γ-T-3 to the brain. In contrast, normal young rats fed the same diet did not exhibit brain localization. Furthermore, the T-3 inhibited age-related decreases in the expression of certain blood brain barrier (BBB) proteins, including caludin-5, occludin and junctional adhesion molecule (JAM). It was found that the activation of the cellular proto-oncogene c-Src and extracellular signal-regulated protein kinase (ERK), in the mitogen-activated protein kinase (MAPK) cell signaling pathway for neuronal cell death, was markedly inhibited by T-3. These results may reveal that aging induces partial BBB disruption caused by oxidative stress, thereby enabling the transport of T-3 through the BBB to the central nervous system, whereupon neuronal protection may be mediated by inhibition of c-Src and/or ERK activation, resulting in an improvement in age-related cognitive deficits. ©2016 JCBN. Source


Kaneai N.,Shibaura Institute of Technology | Fukui K.,Shibaura Institute of Technology | Koike T.,Eisai Food and Chemical Co. | Urano S.,Shibaura Institute of Technology
Biological and Pharmaceutical Bulletin | Year: 2013

This study examines the ability of vitamin E to inhibit hyperoxia-induced loss of soluble N-ethylmaleimide- sensitive fusion protein attachment protein receptor (SNARE) proteins in the neuronal cytoplasm. Here, the effects of vitamin E on hyperoxia-induced changes in the expressions of N-ethylmaleimide-sensitive factor (NSF) and soluble NSF-attachment protein α (α-SNAP) in the rat brain were analyzed. When rats were subjected to hyperoxia, the expression of both SNARE proteins was markedly decreased compared to normal rats. Vitamin E significantly inhibited the decrease in the expression of NSF in rats subjected to hyperoxia. Rats showed the tendency to improve the loss of α-SNAP by vitamin E-supplementation, although it was not statistically significant. On the other hand, vitamin E deficient rats showed marked loss of these proteins in the brain in the absence of oxidative stress. These results suggest that hyperoxia induces a loss of SNARE proteins, which are involved in membrane docking between synaptic vesicles and pre-synaptic membranes, and that vitamin E prevents the oxidative damage of SNARE proteins. Consequently, it is implied that vitamin E inhibits impaired neurotransmission caused by oxidative stress through the prevention of oxidative damage to SNARE proteins by probably its antioxidant effect. © 2013 The Pharmaceutical Society of Japan. Source


Ouchi A.,Ehime University | Nagaoka S.-I.,Ehime University | Suzuki T.,Eisai Co. | Izumisawa K.,Eisai Co. | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014

Measurements of aroxyl radical (ArO•)-scavenging rate constants (ks AOH) of antioxidants (AOHs) [α-, β-, γ-, and δ-tocopherols (TocHs) and -tocotrienols (Toc-3Hs)] were performed in ethanol solution via stopped-flow spectrophotometry. k s AOH values of α-, β-, γ-, and δ-Toc-3Hs showed good agreement with those of the corresponding α-, β-, γ-, and δ- TocHs. ks AOH values were measured not only for each antioxidant but also for mixtures of two antioxidants: (i) α-TocH with β-, γ-, or δ-TocH and (ii) α-TocH with α-, β-, γ-, or δ-Toc-3H. A synergistic effect in which the ks AOH value increases by 12% for γ-TocH (or by 12% for γ-Toc-3H) was observed for solutions including α-TocH and γ-TocH (or γ-Toc-3H). On the other hand, a cancel effect in which the ks AOH value decreases (a) by 7% for β-TocH (or 11% for β-Toc-3H) and (b) by 24% for δ-TocH (or 25% for δ-Toc-3H) was observed for solutions including two kinds of antioxidants. However, only a synergistic effect may function in edible oils, because contents of β- and δ-TocHs (and β- and δ-Toc-3Hs) are much less than those of α- and γ-TocHs (and α- and γ-Toc-3Hs) in many edible oils. UV-vis absorption of α-Toc •, which was produced by reaction of α-TocH with ArO •, decreased remarkably for coexistence of α-TocH with β-, γ-, or δ-TocH (or β-, γ-, or δ-Toc-3H), indicating that the prooxidant effect of α-Toc• is suppressed by the coexistence of other TocHs and Toc-3Hs. © 2014 American Chemical Society. Source


Nakaso K.,Tottori University | Horikoshi Y.,Tottori University | Takahashi T.,Tottori University | Hanaki T.,Tottori University | And 4 more authors.
Neuroscience Letters | Year: 2016

Neuroprotection following signal transduction has been investigated recently as a strategy for Parkinson's disease (PD) therapy. While oxidative stress is important in the pathogenesis of PD, neuroprotection using antioxidants such as α-tocopherol have not been successful. δ-tocotrienol (δT3), a member of the vitamin E family, has received attention because of activities other than its antioxidative effects. In the present study, we examined the estrogen receptor-β (ERβ)-mediated neuroprotective effects of δT3 in a mouse model of PD. ERβ is expressed in neuronal cells, including dopaminergic neurons in the substantia nigra. Daily forced oral administration of δT3 inhibited the loss of dopaminergic neurons in the substantia nigra. In addition, the ER inhibitor tamoxifen canceled the neuroprotective effects of δT3. Moreover, δT3 administration improved the performance of the PD mice in the wheel running activity, while tamoxifen inhibited this improved performance. These results suggest that the oral administration of δT3 may be useful in the treatment of PD patients, and ERβ may be a candidate target for the neuroprotection activity of δT3. © 2015 Elsevier Ireland Ltd. Source


Gong D.,Dalian Medical University | Geng C.,Dalian Medical University | Jiang L.,Dalian Medical University | Wang L.,Dalian Medical University | And 2 more authors.
Journal of Medicinal Food | Year: 2011

We investigated the restorative effect of orally administered olive leaf extract (OLE) on experimentally produced cartilaginous injuries in rabbits. In total, three holes in the left stifle joint, including one in the medial trochlear ridge and two in the trochlear sulcus (proximal and distal) of articular cartilage, were prepared surgically using a drill. For the control group only tap water alone was administered daily, and for the OLE group a water-based solution of OLE (500 mg/kg/day) was administered daily. The injured areas were observed macroscopically and histologically at 3 weeks after the operation. The results indicate that OLE facilitated healing of the three holes and increased the weight of the biceps femoris muscle. Histological examination revealed that in the OLE group, matured cartilage tissues and connective tissues were mixed with regenerated or maturing cartilage tissues with massive proliferation in the injured parts, around which the proliferation of undifferentiated blast cells and the tissue with cartilage substrates were observed. The histological score of the OLE group was significantly lower than that of the control group. The percentage of proliferating cell nuclear antigen+positive cartilage cells in the OLE group was higher than in the control group. Mean density of the restored area observed with Safranin O staining was higher in the OLE group than in the control group. Therefore, OLE is effective for enhancing the healing of cartilaginous injuries. OLE may also have a beneficial effect of slowing and reducing the pathogenesis of degenerative joint diseases in humans. Copyright 2011, Mary Ann Liebert, Inc. Source

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